1. Field of the Invention
The present invention relates to an optical recording medium drive apparatus adapted to record and/or read a signal on/from an optical recording medium by illuminating the optical recording medium with light, and a method of determining the number of layers of an optical recording medium.
2. Description of the Related Art
One technique to record and read digital data is to use an optical disk (or magneto-optical disk) such as a CD (Compact Disc), a MD (Mini-Disc), or a DVD (Digital Versatile Disc) as a recording medium. The optical disk recording medium (hereinafter referred to simply as the optical disk) is a generic expression of recording media configured in the form of a disk on which a signal is recorded in the form of pits or marks so that the signal can be read by illuminating the disk with laser light and detecting a change in intensity of reflected light.
A disk drive for recording/reading data on/from an optical disk can be configured to handle a plurality of types of optical disks. Parameters used in the recording/reading operation are different depending on the type of the optical disk. Therefore, when an optical disk is mounted on the disk drive, the disk drive determines the type of the mounted optical disk.
When an optical disk of a certain type has a plurality of recording layers, it is necessary to detect the number of recording layers.
In general, an optical disk has physical property information recorded thereon to indicate physical properties such as the type of the disk, the number of recording layers, and so on, so that the disk drive can determine the type of the disk, the number of recording layers, etc. by reading the physical property information.
For further information about related techniques, see, for example, Japanese Unexamined Patent Application Publication No. 2006-155791.